Portable electronic still cameras are widely used, which convert an optical image of a subject to an electric image signal through a CCD image sensor or the like, convert the image signal to digital image data, and write the image data frame by frame as still images in a memory. Also an instant printer that uses instant film for printing hard copies of still images based on their image data, and an electronic still camera incorporated with such an instant printer have been known.
In the above mentioned instant printers, so-called mono-sheet type instant films are widely used. The mono-sheet type instant film is mainly constituted of a protective sheet for an image receiving photosensitive layer, the image receiving photosensitive layer, an image transferred layer and a protective sheet for the image transferred layer, which are laminated in this order from a photosensitive surface. A pod containing processing fluid is provided along a leading end of the instant film. While the instant film after exposed is being ejected through a pair of spread rollers, the pod is ruptured and the processing fluid is spread between the image receiving photosensitive layer and the image transferred layer. Thereby, an image formed on the image receiving photosensitive layer is transferred to the image transferred layer, so a positive image is developed in a few minutes. The mono-sheet type instant film is further classified into a transparent type where the image appears on the opposite side from the photosensitive surface, and a reflective type where the image appears on the photosensitive surface. Beside the mono-sheet type, another kind of instant film, called peel-apart type, may be used in the instant printer. In the peel-apart type instant film, a negative sheet (an image receiving photosensitive layer) is exposed and then put on a positive sheet (an image transferred layer). Then, an image is transferred to the positive sheet by pressing these sheets to each other while spreading the processing fluid between these sheets. Thereafter, the positive sheet is peeled apart from the negative sheet. The instant film is usually provided as a film pack, wherein a plurality of sheets of instant films are packaged in a case, and the case and all are loaded in an instant camera or the like. The film pack is designed such that when a light-shielding sheet is advanced out the case after the film pack is loaded, a predetermined exposure area on the photosensitive side is exposed through an exposure opening that is formed through the case.
The instant printer and the electronic still camera incorporated with the printer comprise a pack loading chamber for loading the film pack, an exposure unit for exposing the photosensitive surface of the instant film, a film developing ejecting mechanism including the spread rollers that spread the processing fluid while feeding the exposed instant film to the outside, many kinds of operating members, a display section for displaying an image to print, many kinds of circuit sections, mechanical frames for placing and securing these elements, and an outer cover members.
Among the above mechanisms, the film developing ejecting mechanism fundamentally has the same constructions and the same functions as that used in conventional instant cameras, such as disclosed in JPA No. 4-194832. Exemplary of the exposure unit is disclosed in JPA Nos. 6-83243 and 8-271995, wherein a color image is printed by a printing head with a light emitting element array that moves relative to the instant film while projecting red, green and blue printing light beams. The light emitting element array consists of a plurality of light emitting elements that are arranged in a line and emit light beams responsive to processed image data.
In the above mentioned film pack of the instant films, the instant films are a little smaller than an internal size of the case, to provide clearances between the instant films and the casing, for allowing the exposed instant film to be sent out or drawn out smoothly. Because there are clearances, the instant films may deviate inside the case if a shock or another factor is applied. Therefore, the exposure area is not always placed in a predetermined position behind the exposure opening of the case.
If the instant film deviates, some part of the exposure area would not be exposed to printing light. Since the unexposed part of the exposure area will be colored black when the image is developed to be positive, it damages the image. Also in a printer where the instant film is individually loaded, the same problem may be caused by the deviation inside a film loading chamber.
Meanwhile, the photosensitive surfaces of the instant films loaded in the instant printer or in the printer-incorporated electronic still camera should be completely shielded from ambient light. However, there are so many kinds of light that might reach the photosensitive surfaces of the instant films, such as light leaking through gaps between the cover members and the various operation members, light leaking through joints between the cover members, and light leaking from a illumination device that illuminates an LCD panel from the back. Therefore, it has been difficult to shield the photosensitive surfaces completely from light.
The present invention is made to solve the above problems, and has an object to provide an instant printer and a printing method for use in the instant printer, wherein the exposure area would be entirely exposed even if the instant film deviates inside the case or the printer when the instant film is exposed by the printing head.
The present invention also has an object to provide an instant printer that effectively shield ambient light that might reach the photosensitive surfaces of the instant films.
Another object of the present invention is to provide a printer-incorporated electronic still camera, which is capable of writing and reading photographed image data on external memories.